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A Publication Featuring The Information Services Technology of Maine State Government

Volume V, Issue 11 December 2002

Christmas Trees

Calais, Maine - City on the Edge of Forever

By Harold E. Nelson

My apologies to Star Trek fans for borrowing the title of this article from a well known classic Star Trek episode from the 1960s, but the recurring role that Calais has played regarding historical geodetic surveys, and its significant role bringing precise longitude from the Greenwich Observatory to Harvard College Observatory, indicates that this small city, on the international border with New Brunswick, is more than meets the eye, and is a place to watch in the future.

Calais has seen various forms of geodetic survey work over the past 200 years! From about 1909 to 1919, the International Boundary Commission surveyed and defined the Maine-New Brunswick border as described by treaties between the two countries. The 1893 Annual Report of the Coast Survey mentions Calais’ role in the Coast Survey display at the 1893 World’s Columbian Exposition in Chicago as follows.

"On the southern edge of the floor space, and far enough from the base apparatus to admit an aisle, was located an 11 by 14 inch Dee press, on which the plate printer and his helper struck off from a small engraved copper plate prepared expressly for this purpose copies of a little chart of the St. Croix River, Maine. This exhibit always attracted a large and interested throng, and the prints were eagerly sought after. As the plate printer was plied with numerous questions and had to make frequent explanations of the process, it was impossible for him to work fast enough to supply more than a fraction of the demand. However, the office provided for this deficiency by sending on some thousands of photolithograph copies".

Calais Map Map of Calais distributed at the 1893 World's Columbian Exposition in Chicago.

With all the independent maps of America’s coastline, the determination of precise longitude in America was one of the first steps in building a 19th Century Geographic Information System, making all the Coast Survey maps relative to the world.

With the invention of the electromagnetic telegraph by Crooke and Wheatstone in England, and perfection of Samuel Morse’s version in the U.S., the Naval Observatory in Washington D.C. and the U.S. Coast Survey began experimenting with timing star passages between local meridians via electromagnetic signals over the telegraph lines. In 1851, the Harvard Observatory (the cardinal point of longitude in the U.S.) was connected to the Thomas Hill Observatory in Bangor, Maine, and the longitude difference determined there. Similar work pushed south towards Louisiana. In 1857 we saw the push from Bangor to Calais, and the setting of the stones at Calais to support the clock and telescopes, which are still on the grounds today.

William Brydone Jack, Astronomer at King’s College Observatory in New Brunswick, visited the Coast survey for the 1857 observations at Calais to view and report on the "American Method" of telegraphic longitude determination. Jack also exchanged several star signals with Fredericton. The American Method entailed a written record on a drum register showing time ticks and star signals to the hundredth of a second. Jack had only been using the "eye and ear" method as his finances did not allow for such precise equipment.


Chronograph: Recorded time ticks from the Astronomical Clock, and the star signals placed when the observer tapped a telegraph key when the star crossed the vertical wire in the telescope.

When the ship Great Eastern landed the Transatlantic Telegraph Cable in 1866 spanning the Atlantic from Ireland to Newfoundland, the Coast Survey sent two men to Calais, two to Newfoundland, and two to Ireland. The telegraphic longitude difference was determined across the Atlantic first, but the telegraph lines between Calais and Newfoundland were not good. The situation remedied itself though when a sharp December frost through the lines produced a near perfect connection! Final observations of telegraphic longitude determination were completed on December 16, 1866, at the Calais Observatory.

In 1904, longitude determined by telegraphic means encircled the Earth, closing the angle less than one second (time) from all the independently adjusted observations. Before telegraphic longitude, "time" was physically transported between Liverpool and Boston via "chronometer crossings" on steamers. Later advances included time via wireless telegraphy, and then shortwave time signals. The shortwave method did not require meridian differences to be determined, as Greenwich Mean Time was provided directly to the survey station site. It is interesting to note that some sort of optical astronomical observations were still needed up until the advent of the 1980’s Navstar GPS system of satellites.

Calais has seen better economic times in the past 200 years than it currently enjoys, but a few good things are in the offing for Calais: a new Heritage Center to honor the first European settlers at St. Croix Island in 1604 (, and a new international bridge and Customs center ( I am privileged to help set up and work on the GPS and terrestrial surveys for the new bridge, and follow in the footsteps of those using 19th century state-of-the-art "Global Positioning", where Calais again, will be the site where the most modern surveying methods is used.

Harold E. Nelson ( ) is a 25 year employee of the Maine Department of Transportation’s Photogrammetry and Control Unit. He is currently assigned to processing, adjusting, and integrating the Unit’s precise GPS surveys with terrestrial surveys of other departmental units. The Unit also has led the way nationwide in Airborne GPS photogrammetric mapping procedures, one of which will be done for Calais. Mr. Nelson is proposing that the City of Calais obtain the property known as the Calais Observatory and create a "Meridian Park", recognizing the site on the National Historic Register, and setting up historical informational markers. He considers this site is as important to the surveying and mapping community, as the Golden Spike is to the railroad industry.

CALO Panorama.JPG (112332 bytes)

CALO Panorama: Calais Observatory. The tall stone probably was the mounting for the Hardy Astronomical clock. A pendulum dipped in a pool of mercury in an iron jar which created the time ticks on the chronograph.

Christmas Trees

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